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Memorias Do Instituto Oswaldo Cruz Jun 2003Trypanosoma rangeli, a parasite generally considered non-pathogenic for man, is the second species of human trypanosome to be reported from the New World. The... (Review)
Review
Trypanosoma rangeli, a parasite generally considered non-pathogenic for man, is the second species of human trypanosome to be reported from the New World. The geographical distribution of T. rangeli often overlaps with that of T. cruzi, the same vertebrate and invertebrate hosts being infected. Their differentiation thus becomes of real, practical importance, particularly as they share approximately half the antigenic determinants recognized by the humoral response. Little is known about the life cycle of T. rangeli in the vertebrate host, although thousands of human and wild animal infections have been reported. Recent studies have revealed 2 major phylogenetic lineages in T. rangeli having different characteristics, thus leading to better understanding of the epidemiology and interactions with this parasite's vertebrate hosts and triatomine vectors. Based on further genetic characterization analysis, the authors have proposed 2 alternative hypotheses and consider that T. rangeli could have had clonal evolution or have been subjected to speciation processes.
Topics: Animals; DNA, Kinetoplast; Disease Reservoirs; Evolution, Molecular; Host-Parasite Interactions; Humans; Insect Vectors; Isoenzymes; Trypanosoma
PubMed: 12937750
DOI: 10.1590/s0074-02762003000400001 -
Vector Borne and Zoonotic Diseases... Feb 2020is an avirulent flagellate protozoan that could mislead correct diagnosis of infection, the causative agent of Chagas' disease, given their high similarity. Besides,...
is an avirulent flagellate protozoan that could mislead correct diagnosis of infection, the causative agent of Chagas' disease, given their high similarity. Besides, presents two genetic groups, whose differentiation is achieved mainly by molecular approaches. In this context, ribosomal DNA (rDNA) is a useful target for intra and interspecific molecular differentiation. Analyzing the rDNA of and comparison with other trypanosomatid species, two highly divergent regions (Trβ1 and Trβ2) within the 28Sβ gene were found. Those regions were amplified and sequenced in KP1(+) and KP1(-) strains of , revealing group-specific polymorphisms useful for intraspecific distinction through restriction fragment length polymorphism technique. Also, amplification of Trβ1 allowed differentiation between and Trβ2 predicted restriction length profile, allowed differentiation between , , , and , increasing the use of Trβ1 and Trβ2 beyond a molecular approach for genotyping, but also as a useful target for trypanosomatid classification.
Topics: DNA, Protozoan; DNA, Ribosomal; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Sequence Analysis, DNA; Species Specificity; Trypanosoma; Trypanosoma cruzi; Trypanosoma rangeli
PubMed: 31638479
DOI: 10.1089/vbz.2019.2496 -
Acta Tropica Oct 2020Trypanosoma species (Trypanosomatida, Kinetoplastea) are almost exclusively heteroxenous flagellated parasites, which have been extensively studied as the causative...
Trypanosoma species (Trypanosomatida, Kinetoplastea) are almost exclusively heteroxenous flagellated parasites, which have been extensively studied as the causative agents of severe trypanosomiasis in humans and domestic animals. However, the biology of avian trypanosomes remains insufficiently known, particularly in wildlife, despite information that some species might be pathogenic and affect the fitness of intensively infected individuals. Avian trypanosomes are cosmopolitans. Due to regular bird seasonal migrations, this host-parasite system might provide new insight for better understanding mechanisms of transcontinental dispersal of pathogens, their ecological plasticity, specificity and speciation. Trypanosoma everetti parasitizes numerous bird species globally, but data on its biology are scarce and its vectors remain unknown. This study aimed to test experimentally whether widespread Culicoides (Diptera: Ceratopogonidae) biting midges are susceptible to infection with this parasite. Two common house martins Delichon urbicum and two sedge warblers Acrocephalus schoenobaenus naturally infected with T. everetti were caught in the wild after arrival from African wintering grounds. Laboratory reared Culicoides nubeculosus and wild-caught Culicoides impunctatus biting midges were exposed by allowing them to take infected blood meals. The experimentally infected and control insects were maintained in the laboratory and dissected at intervals to follow the development of the parasite. Infections were determined using microscopic examination and PCR-based testing. Four closely related haplotypes of T. everetti were found, and each was present in different individual parasite-donor birds. These parasites readily developed and produced metacyclic trypomastigotes in C. nubeculosus and C. impunctatus biting midges. Molecular characterisation of T. everetti was developed. According to Bayesian phylogenetic analysis using a DNA fragment encoding 18S rRNA, the five species of small avian trypanosomes were closely related. Wild caught Culicoides biting midges were also collected and screened for the presence of natural infections. In all, 6.8% of wild-caught biting midges belonging to five Culicoides species were PCR-positive for kinetoplastids, including Trypanosoma species. Culicoides biting midges are readily susceptible and likely naturally transmit avian trypanosomes and thus, should be targeted in epidemiology research of avian trypanosomiasis.
Topics: Animals; Bird Diseases; Ceratopogonidae; Humans; Insect Vectors; Trypanosoma; Trypanosomiasis
PubMed: 32473117
DOI: 10.1016/j.actatropica.2020.105555 -
Frontiers in Cellular and Infection... 2013African trypanosomes are sustained in the bloodstream of their mammalian hosts by their extreme capacity for antigenic variation. However, for life cycle progression,... (Review)
Review
African trypanosomes are sustained in the bloodstream of their mammalian hosts by their extreme capacity for antigenic variation. However, for life cycle progression, trypanosomes also must generate transmission stages called stumpy forms that are pre-adapted to survive when taken up during the bloodmeal of the disease vector, tsetse flies. These stumpy forms are rather different to the proliferative slender forms that maintain the bloodstream parasitaemia. Firstly, they are non proliferative and morphologically distinct, secondly, they show particular sensitivity to environmental cues that signal entry to the tsetse fly and, thirdly, they are relatively robust such that they survive the changes in temperature, pH and proteolytic environment encountered within the tsetse midgut. These characteristics require regulated changes in gene expression to pre-adapt the parasite and the use of environmental sensing mechanisms, both of which allow the rapid initiation of differentiation to tsetse midgut procyclic forms upon transmission. Interestingly, the generation of stumpy forms is also regulated and periodic in the mammalian blood, this being governed by a density-sensing mechanism whereby a parasite-derived signal drives cell cycle arrest and cellular development both to optimize transmission and to prevent uncontrolled parasite multiplication overwhelming the host. In this review we detail recent developments in our understanding of the molecular mechanisms that underpin the production of stumpy forms in the mammalian bloodstream and their signal perception pathways both in the mammalian bloodstream and upon entry into the tsetse fly. These discoveries are discussed in the context of conserved eukaryotic signaling and differentiation mechanisms. Further, their potential to act as targets for therapeutic strategies that disrupt parasite development either in the mammalian bloodstream or upon their transmission to tsetse flies is also discussed.
Topics: Adaptation, Physiological; Animals; Blood; Gene Expression Regulation; Humans; Mammals; Trypanosoma; Tsetse Flies
PubMed: 24294594
DOI: 10.3389/fcimb.2013.00078 -
ELife May 2023African trypanosomes proliferate as bloodstream forms (BSFs) and procyclic forms in the mammal and tsetse fly midgut, respectively. This allows them to colonise the host...
African trypanosomes proliferate as bloodstream forms (BSFs) and procyclic forms in the mammal and tsetse fly midgut, respectively. This allows them to colonise the host environment upon infection and ensure life cycle progression. Yet, understanding of the mechanisms that regulate and drive the cell replication cycle of these forms is limited. Using single-cell transcriptomics on unsynchronised cell populations, we have obtained high resolution cell cycle regulated (CCR) transcriptomes of both procyclic and slender BSF without prior cell sorting or synchronisation. Additionally, we describe an efficient freeze-thawing protocol that allows single-cell transcriptomic analysis of cryopreserved . Computational reconstruction of the cell cycle using periodic pseudotime inference allowed the dynamic expression patterns of cycling genes to be profiled for both life cycle forms. Comparative analyses identify a core cycling transcriptome highly conserved between forms, as well as several genes where transcript levels dynamics are form specific. Comparing transcript expression patterns with protein abundance revealed that the majority of genes with periodic cycling transcript and protein levels exhibit a relative delay between peak transcript and protein expression. This work reveals novel detail of the CCR transcriptomes of both forms, which are available for further interrogation via an interactive webtool.
Topics: Trypanosoma; Single-Cell Gene Expression Analysis; Cryopreservation; RNA, Protozoan; Protozoan Proteins
PubMed: 37166108
DOI: 10.7554/eLife.86325 -
Trends in Parasitology Jun 2013The clonal theory of parasitic protozoa has been recently challenged by researchers stating that recombination in Kinetoplastida is much more frequent than previously...
The clonal theory of parasitic protozoa has been recently challenged by researchers stating that recombination in Kinetoplastida is much more frequent than previously believed, or that selfing and homogamy should be distinguished from 'strict' clonality. These researchers and many others show that the concept of clonality proposed by us is not correctly understood. A recapitulation of the clonal theory will thus be addressed herein. Comparisons with various other pathogens evidence general features among them and enhance our understanding of Trypanosoma and Leishmania population genetics. The relevance is considerable not only for our knowledge of the basic biology of these organisms but also for applied research: molecular epidemiology (strain-typing), clinical research, vaccine and drug design, and experimental evolution.
Topics: Animals; Biological Evolution; Genetic Variation; Hybridization, Genetic; Leishmania; Trypanosoma
PubMed: 23602631
DOI: 10.1016/j.pt.2013.03.007 -
Anais Da Academia Brasileira de Ciencias Sep 2005This review outlines aspects on the developmental stages of Trypanosoma cruzi and Trypanosoma rangeli in the invertebrate host, Rhodnius prolixus. Special attention is... (Review)
Review
This review outlines aspects on the developmental stages of Trypanosoma cruzi and Trypanosoma rangeli in the invertebrate host, Rhodnius prolixus. Special attention is given to the interactions of these parasites with gut and hemolymph molecules and the effects of the organization of midgut epithelial cells on the parasite development. The vector insect's permissiveness to T. cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain and the molecular interactions with trypanolytic compounds, lectins and resident bacteria in the gut. T. rangeli invades the hemocoel and once in the hemolymph, can be recognized and activates the defense system of its insect vector, i.e., the prophenoloxidase system, phagocytosis, hemocyte microaggregation, superoxide and nitric oxide activity and the eicosanoid biosynthesis pathway. Taken together, these findings not only provide a better understanding of the interactions parasite-insect vector, but also offer new insights into basic physiological processes involved in the parasites transmission.
Topics: Animals; Hemolymph; Host-Parasite Interactions; Insect Vectors; Rhodnius; Trypanosoma; Trypanosoma cruzi
PubMed: 16127548
DOI: 10.1590/s0001-37652005000300004 -
Memorias Do Instituto Oswaldo Cruz 1999Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping... (Review)
Review
Trypanosoma rangeli is a hemoflagelate parasite that infects domestic and sylvatic animals, as well as man, in Central and South America. T. rangeli has an overlapping distribution with T. cruzi, the etiological agent of Chagas disease, sharing several animal reservoirs and triatomine vectors. We have isolated T. rangeli strains in the State of Santa Catarina, in southern Brazil, which dramatically increased the distribution area of this parasite. This brief review summarizes several studies comparing T. rangeli strains isolated in Santa Catarina with others isolated in Colombia, Honduras and Venezuela. The different methods used include indirect immunofluorescence and western blot assays, lectin agglutination, isoenzyme electrophoresis and random amplified polymorphic DNA analysis, triatomine susceptibility, in vitro cell infection assays, and mini-exon gene analysis.
Topics: Animals; Central America; DNA, Protozoan; Humans; Isoenzymes; Life Cycle Stages; Phylogeny; South America; Trypanosoma
PubMed: 10224529
DOI: 10.1590/s0074-02761999000200015 -
Current Pharmaceutical Design 2007Trypanosoma brucei rhodesiense and T. b. gambiense are the causative agents of sleeping sickness, a fatal disease that affects 36 countries in sub-Saharan Africa.... (Comparative Study)
Comparative Study Review
Trypanosoma brucei rhodesiense and T. b. gambiense are the causative agents of sleeping sickness, a fatal disease that affects 36 countries in sub-Saharan Africa. Nevertheless, only a handful of clinically useful drugs are available. These drugs suffer from severe side-effects. The situation is further aggravated by the alarming incidence of treatment failures in several sleeping sickness foci, apparently indicating the occurrence of drug-resistant trypanosomes. Because of these reasons, and since vaccination does not appear to be feasible due to the trypanosomes' ever changing coat of variable surface glycoproteins (VSGs), new drugs are needed urgently. The entry of Trypanosoma brucei into the post-genomic age raises hopes for the identification of novel kinds of drug targets and in turn new treatments for sleeping sickness. The pragmatic definition of a drug target is, a protein that is essential for the parasite and does not have homologues in the host. Such proteins are identified by comparing the predicted proteomes of T. brucei and Homo sapiens, then validated by large-scale gene disruption or gene silencing experiments in trypanosomes. Once all proteins that are essential and unique to the parasite are identified, inhibitors may be found by high-throughput screening. However powerful, this functional genomics approach is going to miss a number of attractive targets. Several current, successful parasiticides attack proteins that have close homologues in the human proteome. Drugs like DFMO or pyrimethamine inhibit parasite and host enzymes alike--a therapeutic window is opened only by subtle differences in the regulation of the targets, which cannot be recognized in silico. Working against the post-genomic approach is also the fact that essential proteins tend to be more highly conserved between species than non-essential ones. Here we advocate drug targeting, i.e. uptake or activation of a drug via parasite-specific pathways, as a chemotherapeutic strategy to selectively inhibit enzymes that have equally sensitive counterparts in the host. The T. brucei purine salvage machinery offers opportunities for both metabolic and transport-based targeting: unusual nucleoside and nucleobase permeases may be exploited for selective import, salvage enzymes for selective activation of purine antimetabolites.
Topics: Animals; Antiprotozoal Agents; Drug Delivery Systems; Humans; Trypanosoma brucei brucei; Trypanosoma brucei gambiense; Trypanosoma brucei rhodesiense; Trypanosomiasis, African
PubMed: 17346174
DOI: 10.2174/138161207780162809 -
Transactions of the Royal Society of... 1988
Topics: Animals; Trypanosoma; Trypanosoma brucei brucei
PubMed: 3256130
DOI: 10.1016/0035-9203(88)90552-4